delete Pro status

My wife used my son's Mii to play boxing. Apparently she got pretty high status. When my 6 years old son started to play boxing, his Mii was on that Pro status because of my wife. (he gets knocked around a lot :-( ) I would like him to start from the beginning. How do I delete his status without deleting mine. I read the manual but nothing about it. Only deleting Mii. Is that the only way to remove his profile/status? Any help would be great. I am setting up a Mommy Mii after this.

First of all, I want to apologize to skool sucks. My second question was for you to answer and I pasted the wrong name. Yes, I copy the Mii onto the controller. Haven't test it yet, but I am sure it will work. Thanks again - to all those who replied my post.